﻿/* ==============================================================================
*
*   Copyright (c) 2010, Pierre Favier
*   All rights reserved.
*
*   NTasking is free software: you can redistribute it and/or modify it
*   under the terms of the GNU General Public License as published by the
*   Free Software Foundation.
*
*   Redistribution and use in source and binary forms, with or without
*   modification, are permitted provided that the following conditions
*   are met:
*
*   -   Redistributions of source code must retain the above copyright notice,
*       this list of conditions and the following disclaimer.
*
*   -   Redistributions in binary form must reproduce the above
*       copyright notice, this list of conditions and the following
*       disclaimer in the documentation and/or other materials
*       provided with the distribution.
*
*   THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
*   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
*   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
*   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
*   BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
*   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
*   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
*   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
*   ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
*   TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
*   THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
*   SUCH DAMAGE.
*
* ============================================================================== */

using System;
using System.Reflection;

namespace NTasking.Internals
{

    /// <summary>
    /// Implement Extensions to the <see cref="System.Exception"/> class
    /// </summary>
    public static class ExceptionEx
    {

        private static readonly Action<Exception> _internalPreserveStackTrace;
        private static readonly Func<Exception, Exception> _internalPrepForRemoting;


        /// <summary>
        /// Initializes the <see cref="ExceptionEx"/> class.
        /// </summary>
        static ExceptionEx()
        {
            // Get some internal methods from Exception and create delegates to call them
            MethodInfo method = typeof(Exception).GetMethod("InternalPreserveStackTrace", BindingFlags.Instance | BindingFlags.NonPublic);
            _internalPreserveStackTrace =
                (Action<Exception>)
                Delegate.CreateDelegate(typeof(Action<Exception>), null, method);

            method = typeof(Exception).GetMethod("PrepForRemoting", BindingFlags.Instance | BindingFlags.NonPublic);
            _internalPrepForRemoting =
                (Func<Exception, Exception>)
                Delegate.CreateDelegate(typeof(Func<Exception, Exception>), null, method);
        }


        /// <summary>
        /// Preserves the stack trace of the given exception before rethrowing it.
        /// </summary>
        /// <param name="exception">The exception which stack trace has to be preserved.</param>
        /// <param name="remote">
        /// If set to <c>true</c>, the stack trace preservation will include indications that the
        /// trace has been remotely generated (i.e. in an Accept statement within a <see cref="Task"/>.
        /// </param>
        public static void PreserveStackTrace(this Exception exception, bool remote)
        {
            if (remote)
                _internalPrepForRemoting(exception);
            else
                _internalPreserveStackTrace(exception);
        }

    }

}
